Trocar seal system

ABSTRACT

A seal assembly is provided for reception of an elongated surgical instrument, which comprises a body having at least one opening configured and dimensioned to permit entry of an elongated surgical instrument and defining a central longitudinal axis; a seal member formed of a resilient material and defining an aperture therein, the aperture being configured and dimensioned such that insertion of the surgical instrument into the aperture causes the resilient material defining the aperture to resiliently contact the outer surface of the surgical instrument in a substantially fluid tight manner, the seal member further including a peripheral flange element which contacts a surface of the body to form a contact seal therewith; and a fabric layer juxtaposed relative to the resilient material. The seal assembly may further include a coating applied to the seal member to reduce friction between the seal member and surgical instrumentation inserted therein. The coating is preferably a hydrocyclosiloxane membrane prepared by plasma polymerization process.

BACKGROUND

1. Technical Field

The present disclosure relates to seal systems of the type adapted toallow the introduction of a surgical instrument into a patient's body.In particular, the disclosure relates to a seal system to be used incombination with a cannula assembly where the cannula assembly isintended for insertion into a patient's body and an instrument isinserted into the patient's body through the cannula.

2. Background of Related Art

Laparoscopic procedures are performed in the interior of the abdomenthrough a small incision, e.g., through narrow endoscopic tubes orcannulas inserted through a small entrance incision in the skin.Minimally invasive procedures are performed elsewhere in the body, e.g.,in the chest, and are often generally referred to as “endoscopic”procedures. Minimally invasive or endoscopic procedures generallyrequire that any instrumentation inserted into the body be sealed, i.e.provisions must be made to ensure that gases do not enter or exit thebody through the endoscopic incision as, for example, in surgicalprocedures in which the surgical region is insufflated. Moreover,endoscopic procedures often require the surgeon to act on organs,tissues, and vessels far removed from the incision, thereby requiringthat any instruments used in such procedures be relatively long andnarrow.

For such procedures, the introduction of a tube into certain anatomicalcavities such as the abdominal cavity is usually accomplished by use ofa system incorporating a trocar and cannula assembly. A cannula assemblyis formed of a cannula attached to a cannula housing which generallyincludes seal assembly adapted to maintain a seal across the opening ofthe seal assembly both with and without an instrument insertedtherethrough. Since the cannula is in direct communication with theinternal portion of the seal assembly, insertion of the cannula into anopening in the patient's body so as to reach the inner abdominal cavityshould be adapted to maintain a fluid tight interface between theabdominal cavity and the outside atmosphere.

Since minimally invasive surgical procedures in the abdominal cavity ofthe body generally require insufflating gases to raise the cavity wallaway from vital organs, the procedure is usually initiated by use of aVerres needle through which a gas is introduced into the body cavity.The gas provides a slight pressure which raises the wall surface of theperitoneum away from the vital organs thereby providing an adequateregion in which to operate. Thereafter, a trocar assembly which includesa cannula and a trocar or obturator is inserted within the cannula topuncture the peritoneum, i.e. the inner lining of the abdominal cavitywall. The obturator is removed and laparoscopic or endoscopic surgicalinstruments may then be inserted through the cannula to perform surgerywithin the abdominal cavity. The cannula may also be utilized forintroducing tubes into the body as for drainage purposes, for specimenremoval, for diagnostic evaluations, or the like.

In view of the need to maintain the atmospheric integrity of the innerarea of the cavity, a seal assembly for a cannula which permitsintroduction of an obturator and a wide range of surgical instrumentsand which maintains the atmospheric integrity of the inner area of thecavity is desirable. Generally, in the context of insufflatory,minimally invasive surgical procedures, cannula assemblies includestructure(s) that satisfy two sealing requirements. The firstrequirement is to provide a substantially fluid tight seal when aninstrument is not present in the cannula. The second requirement is toprovide a substantially fluid tight seal when an instrument is beingintroduced into or already is present in the cannula. In this regard,there have been a number of attempts in the prior art to provide suchsealing requirements.

U.S. Pat. No. 4,655,752 to Honkanen et al. teaches a cannula including ahousing and first and second seal members. The first seal member isconically tapered toward the bottom of the housing and has a circularopening in its center, while the second seal is conically tapered andcup shaped. The second seal includes at least one slit to allow for thepassage of instruments.

U.S. Pat. No. 4,929,235 to Merry et al. teaches a self-sealing catheterintroducer having a sealing mechanism to prevent blood or fluid leakage.The sealing mechanism includes a planar sealing element having a slitand a conical sealing element. The sealing elements are each adapted tosurround a tube.

U.S. Pat. Nos. 4,874,377 and 5,064,416 to Newgard et al. relate to aself-occluding intravascular cannula assembly in which an elastomericvalving member is positioned transversely to a housing and isperipherally compressed to cause displacement, distortion and/orrheological flow of the elastomeric material. A frustoconical dilatorprojection cooperates with the elastomeric valving member in moving thevalving member to a non-occluding position.

U.S. Pat. No. 5,300,033 to Miller suggests a seal construction includingan elastic body having a cylindrical wall with first and second wallsformed integrally with the cylindrical wall. The second wall includes aslit to permit passage of a surgical instrument and first and secondleaflets which define the slit. The leaflets are thicker in crosssection to provide an additional closing force at the slit.

A disadvantage of several known seal systems for cannulas concerns thedifficulty encountered in inserting and advancing the surgicalinstrument through the seal unit. In particular, since known elastomericseal members are designed to form and maintain a fluid tight seal aboutthe instrument, the aperture or slit within the seal through which theinstrument is passed is of relatively small or narrow dimension.Further, portions of the seal member defining the aperture are generallythick in cross-section to provide a sufficient closing force of the sealabout the instrument. see, e.g., U.S. Pat. No. 5,300,033. As aconsequence of these design considerations, the level of force needed toinsert and advance the instrument through the seal aperture isincreased, thereby requiring awkward maneuvering on the surgeon's behalfto appropriately position the instrument for the desired surgery.Moreover, known seal systems are generally ineffectual in accommodatinginstruments of differing diameter while maintaining acceptable insertionforces and facilitating the range of desired surgical manipulations,e.g., angular instrument movements and specimen removal.

Accordingly, the present disclosure obviates the disadvantages of theprior art by providing a seal unit or assembly for a cannula assembly,which is capable of forming and maintaining a tight seal aboutinstruments of varying diameters inserted through the cannula and whichincorporates structure to enhance and facilitate passage of theinstrument through the seal unit.

SUMMARY

The present disclosure provides a seal assembly for reception of anelongated surgical instrument, which comprises a body having at leastone opening configured and dimensioned to permit entry of an elongatedsurgical instrument and defining a central longitudinal axis; a sealmember formed of a resilient material and defining an aperture therein,the aperture being configured and dimensioned such that insertion of thesurgical instrument into the aperture causes the resilient materialdefining the aperture to resiliently contact the outer surface of thesurgical instrument in a substantially fluid tight manner, the sealmember further including a peripheral flange element which contacts asurface of the body to form a contact seal therewith; and a fabric layerjuxtaposed relative to the resilient material.

The seal assembly may further include a coating applied to the sealmember to reduce friction between the seal member and surgicalinstrumentation inserted therein. The coating is preferably ahydrocyclosiloxane membrane prepared by plasma polymerization process.

In one aspect of the presently disclosed seal assembly a ring member issecured to the seal member and includes a dampening element disposedbetween a surface of the ring member and a surface of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are described herein below with reference to thedrawings wherein:

FIG. 1 is a perspective view of a trocar assembly having the sealassembly of FIG. 2 removably installed thereon;

FIG. 2 is a perspective view of a seal assembly constructed inaccordance with the present disclosure;

FIG. 3 is a cross-sectional view of a seal member constructed inaccordance with the present disclosure;

FIG. 3A is an alternative embodiment of the seal element of FIG. 3;

FIG. 4 is a cross-sectional view of the seal assembly of FIG. 2;

FIG. 5 is a partial cross-sectional view showing the seal body housingtaken along section line 5-5 of FIG. 1;

FIG. 6 is an alternative embodiment of a seal assembly constructed inaccordance with the present disclosure;

FIG. 7 is further alternative embodiment of a seal assembly constructedin accordance with the present disclosure; and

FIG. 8 is an alternative embodiment of a ring element of the presentdisclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawing figures in which like referencenumerals identify similar or identical elements, a seal assembly of thepresent disclosure is illustrated in FIGS. 1-5, and is designatedgenerally as seal assembly 100.

The presently disclosed seal assembly embodiments contemplate theintroduction of various types of surgical instruments adapted forinsertion through an elongated trocar assembly. Examples of suchinstruments include clip appliers, graspers, dissectors, retractors,staplers, laser fibers, photographic devices, endoscopes andlaparoscopes, tubes, and the like. Such instruments are collectivelyreferred to herein as “instruments”.

Referring to FIGS. 1 and 2, seal assembly 100 is used in combinationwith a conventional trocar assembly which includes a cannula assembly110 and a trocar obturator 112. Examples of trocar assemblies in whichthe present seal assembly may be utilized are disclosed in U.S. Pat. No.5,603,702 which issued on Feb. 18, 1997 to Smith et al. and U.S.application Ser. No. 08/546,009 filed Oct. 20, 1995 by Smith et al., theentire contents of each of these disclosures are hereby incorporated byreference.

Seal assembly 100, either alone or in combination with a seal unit/sealassembly internal to cannula assembly 110 provides a substantial sealbetween a body cavity of a patient and the outside atmosphere bothduring and subsequent to insertion of an instrument through the cannula.In this manner, insufflation gases are prevented from escaping throughthe trocar assembly to the outside environment. Seal assembly 100 iscapable of accommodating instruments of varying diameter, e.g., fromabout 5 mm to about 12 mm, while providing a fluid tight seal with theouter diameter of each instrument. The versatility of the presentlydisclosed seal assembly facilitates endoscopic, surgery, wherein avariety of instruments having different diameters are often neededduring a single surgical procedure.

Seal assembly 100 is preferably detachably mountable to the proximal endof cannula assembly 110. Thus, the surgeon can remove seal assembly 100from the cannula assembly 110 at any time during the surgical procedureand, similarly, mount the seal assembly 100 to the cannula when desired.In addition, seal assembly 100 may be readily adapted for mounting toconventional cannulas of differing structures. The detachability of sealassembly 100 from cannula assembly 110 facilitates specimen removalthrough cannula assembly 110.

Referring to FIGS. 3 and 4, seal assembly 100 includes a seal member 118disposed within a body or housing which is formed by the snap fittingtogether of end cap 114 and lower housing member 116. Preferably thehousing components of seal assembly 100 are formed of a polycarbonatematerial such as ABS available from the General Electric Company.

A two part ring assembly which includes ring members 120 and 122 aresnap fitted together on either side of seal member 118. Ring member 120is disposed adjacent the distally facing surface of seal member 118 andring member 122 is disposed on the proximally facing side of seal member118. Ring 120 is provided with holes 120 a and posts 120 b which arealternately disposed around the ring and are aligned with holes 118 a onseal member 118. Ring 122 is provided with posts 122 a and holes 122 bwhich mate with holes 120 a and posts 120 b of ring member 120,respectively by snap fitting together thereby surrounding inner section118 b. Although rings 120 and 122 are shown having alternating holes andposts, one of the rings could have all holes formed therein while theother ring could have all posts aligned with the holes of the otherring. Additionally, greater or fewer holes and posts may be utilized tosecure the two rings together.

A seal clamp 124 is provided within the housing components 114 and 116which secures an O-ring 131 and lower seal 126 with respect to sealassembly 100. Seal clamp 124 is provided with projecting posts 124 awhich fit within openings formed on the proximal side of lower housing116. Seal clamp 124 also serves to secure a proximal flange of a lowerseal 126 which is provided at the distal end of lower housing member116. Lower seal 126 assists in the sealing engagement of seal assembly100 to cannula assembly 110.

As best shown in FIG. 3, seal member 118 includes fabric 128 which ispreferably disposed on both the proximal and distal sides thereof.Fabric 128 may alternatively be disposed on just one of either theproximally facing surface or the distally facing surface. Fabric 128 maybe of any suitable fabric, for example, a SPANDEX material containingabout 20% LYCRA and about 80% NYLON available from Milliken. A sealingflange 129 is formed on the upper outer periphery of seal member 118 andcontacts end cap 114 when seal member 118 is disposed within sealassembly 100.

In one method of forming seal member 118 with fabric 128 a raw, i.e.,uncured polyisoprene plug is first compressed into a flat state, e.g., aflat sheet of polyisoprene. A single layer of fabric is positioned ontop of the flattened polyisoprene sheet and compressed into the uncuredrubber by any suitable compression process such as, for example,calendering. If it is desired to have fabric on both sides of sealmember 118, this process is also accomplished on the other side of thepolyisoprene sheet. The fabric polyisoprene composite is die cut intocircular slugs having an outer diameter and an inner diameter whichforms a central aperture. The slugs are placed in a hot compression moldto cure the polyisoprene. Molding of wing 129 may be simultaneouslyaccomplished.

During the above-described process the bleed-through of the polyisoprenematerial into and/or through the fabric layers is regulated by thedensity of the fabric selected. A greater degree of bleed-through ofpolyisoprene provides greater resistance to fraying of the fabric uponrepeated insertion of instruments through the seal. However, too muchbleed-through of the polyisoprene through the fabric may affectinstrument insertion.

Referring to FIG. 3A, an alternative embodiment of seal member 118 isshown as seal member 218. Seal member 218 is the same as seal member 118in most aspects except that inner section 218 b is formed to have fabriclayer 228 enveloped between upper and lower polyisoprene layers 218 cand 218 d, respectively.

In order to reduce friction between instruments and the seal member,e.g. seal member 118 or seal member 218, as instruments are insertedthrough seal assembly 100, a coating may be applied to the seal member.One coating which has been found particularly effective is ahydrocyclosiloxane membrane prepared by plasma polymerization process.Such a coating is available from Innerdyne, Inc. of Salt Lake City,Utah, U.S.A., and is disclosed in U.S. Pat. No. 5,463,010 which issuedto Hu et al. on Oct. 31, 1995, the entire contents of which are herebyincorporated by reference.

FIG. 5 shows a shaft 130 of a surgical instrument, such as trocarobturator 112 (FIG. 1), inserted through seal assembly 100 and a duckbill valve or “zero” seal valve 132 which prevents the escape ofinsufflation gases in the absence of an instrument in the trocarassembly. As shown in FIG. 5, seal member 118 provides a seal about theperiphery of instrument shaft 130.

Referring to FIG. 6, an alternative embodiment of seal assembly 100 isdesignated generally as seal assembly 300. Seal assembly 300 is the sameas seal assembly 100 except that an inner planar seal member 352 isdisposed in the distal end of seal assembly 100 to provide additionalsealing capability for instruments having larger diameters. Seal element352 has an aperture 354 which has a diameter larger than the diameter ofaperture 156 of seal member 118.

Referring to FIGS. 7 and 8, an alternative feature of the presentlydisclosed seal assembly is a dampening element such as over-moldedcoating 158. Coating 158 may be formed over upper ring 422 byover-molding the ring with material such as polyisoprene so as toenvelope part or all of the ring thereby forming a bumper between thering and the inner surface of upper housing component 114. In thismanner, sealing flange 429 may be formed as a separate element from sealmember 418, i.e., as part of dampening coating 158. Ring 422 is modifiedfrom ring 122 to include peripheral slots 423 which serve to anchorsealing flange 429 as the rubber material forming coating 458 flowsthrough slots 423 prior to curing.

Other dampening element configurations are also contemplated. Forexample, a pad which is secured to the proximal surface of ring 122 maybe provided to dampen the sound created by the impact of the proximalsurface of ring 122 with the inner distal facing surface of housingcomponent 114.

It will be understood that various modifications may be made to theembodiments shown herein. Therefore, the above description should not beconstrued as limiting, but merely as exemplifications of preferredembodiments. Those skilled in the art will envision other modificationswithin the scope and spirit of the presently disclosed seal assemblies.

1. A seal assembly for reception of an elongated surgical instrument,which comprises: a body having at least one opening configured anddimensioned to permit entry of an elongated surgical instrument anddefining a central longitudinal axis; a seal member disposed in the bodyand being formed of a resilient material and defining an aperturetherein, the aperture being configured and dimensioned such thatinsertion of the surgical instrument into the aperture causes theresilient material defining the aperture to resiliently contact theouter surface of the surgical instrument in a substantially fluid tightmanner, the seal member further including a peripheral flange elementwhich contacts a surface of the body to form a contact seal therewith;and a fabric layer juxtaposed relative to the resilient material.